chore(deps): update actions/cache action to v4

Author: renovate[bot]

.github/workflows/mkdocs.yml

@@ -14,7 +14,7 @@ jobs:
       - name: Install asdf
         uses: asdf-vm/actions/setup@v1
       - name: Cache asdf tools
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: |
             /home/runner/.asdf

.github/workflows/test.yml

@@ -11,7 +11,7 @@ jobs:
       - name: Install asdf
         uses: asdf-vm/actions/setup@v1
       - name: Cache tools
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: |
             /home/runner/.asdf
@@ -28,7 +28,7 @@ jobs:
       - name: Get yarn cache directory path
         id: yarn-cache-dir-path
         run: echo "::set-output name=dir::$(yarn cache dir)"
-      - uses: actions/cache@v2
+      - uses: actions/cache@v4
         id: yarn-cache # use this to check for `cache-hit` (`steps.yarn-cache.outputs.cache-hit != 'true'`)
         with:
           path: ${{ steps.yarn-cache-dir-path.outputs.dir }}